The present invention relates, more precisely, to circuit breakers of the type which contain a gas having good dielectric properties, such as sulfur hexafluoride, at a pressure of a few atmospheres.
Further, it relates to puffer type circuit breakers including a chamber in which gas is compressed when the circuit breaker openings and is directed towards the zone where the arcing contacts separate. Further, when interrupting high intensity currents (e.g. short circuits) the arc which is struck between the arcing contacts heats the surrounding gas and increases its pressure.
An air of the present invention is to provide a circuit breaker in which the local pressure increase due to the arc is used to assist in displacing the moving parts of the circuit breaker, thereby reducing the amount of energy required to open the circuit breaker.
Another aim of the invention is to provide a circuit breaker in which the speed at which the moving assembly moves away from the fixed assembly when the circuit breaker is opened increases with increasing intensity of the current to be interrupted.